RE: db block Size for Indexes Tablespaces in 9.2 ?

Hi Arup , List

Your point is Correct about High "buffer busy wait" Contention During Large OLTP Insert /Updates.

High "buffer busy wait" on Corresponding INDEX during INSERT Operations was Observed during our previous benchmark which overcame by Converting to REVERSE Index as the Field Value was Sequentially Increasing .

Following Article advocates HIGHER Block Size for Index , Strangely :-

http://www.tusc.com/oracle/download/author.html#loneyk

What may be the Commonly followed Best practice for DB_BLOCK_SIZE for Index Tablespaces in 9.2 ?

Thanks

-----Original Message-----
Sent: Wednesday, December 18, 2002 12:14 AM To: Multiple recipients of list ORACLE-L

I can't point to a paper or article on that, but based on tests I have done, the block size of index tablespaces for a high volume transaction system should be lower than the table block sizes. 2000 tps with 25 changes each does not sound like a really huge transaction rate. You could set the tables' block size as 8k and indexes' as 4k.

The reason for smaller block sizes in index is simple - to reduce the dreaded buffer busy waits that will inevitably happen for this type of transaction rate. A smaller block size will make sure less number of rows are in a block - making the chance that two sessions are trying to get the same buffer low.

Caveat - if your database has a large percentage of DSS type quries (you mentioned hybrid), then they will suffer slightly as the block gets will increase.

HTH Arup Nanda

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Tuesday, December 17, 2002 11:28 AM

>
> What is the Best Practice for DB_BLOCK_SIZE for Index Tablespaces
Undergoing High Volume of Insert , Update , Selects ? Why ?
>
> Any Docs , Links for the Same ?
>
>
> NOTE - This is for a Hybrid Application Benchmark undergoing 2000 Banking
Transactions per second
> approx.
>
> OLTP Transaction sample = 1 Cash Deposit Transaction undergoing Insert
Update Delete Operations on Total of 5 Tables Each having About 5 Indexes
>
> Thanks
>

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